STROMBECK HILS-CONGLOMERATE ECHINODERMS. 



15 



M. von Strombeck proceeds to describe (pp. 463-652) the species 

 of Echinodermata peculiar to the Hils-conglomerate, and to point 

 out their synonymy, alliances, and localities. 



The following are the species of Echinoidea that have been found 

 in the Hils-conglomerate and determined with precision. 



Toxaster complanatus (GmeL), Ag.... 



Holaster Hardyi, Dub 



Dysaster ovulum, Ag 



Pygurus Montmollini, Ag 



Nucleolites Olfersii, Ag 



Gresslyi, Ag 



Pyrina pygaea, Desor 



Holectypus macropygus, Desor ... 



Diadema rotulaie, Ag 



Bourgueti, Ag , 



Cidaris punctata, Roem , 



cc. 

 cc. 



r. 

 rr. 



c. 



r. 



c. 



r. 



r. 

 rr. 

 cc. 



^43 



o *^ 



' »> V d 



; s <u t> 



n *j S 



S S 2 



t 





S c 



o c* 



« O «C 



*»( y Q^ 



J? a. 



v 



^ o . 



I? M^ 



l-^T! Sin 



3 s b . 

 o s 5 o, 



S e cj o 



All these species, except the last one, occur together more or less 

 frequently ; but exclusively in the lower Hils-conglomerate. The 

 last species {Cidaris punctata) is rare in the same localities, but is 

 extremely abundant where the beds contain no other Urchins. 



M. D'Orbigny has recently divided the Neocomian into two 

 stages, — the lower, or Neocomian proper, — and the upper, or Ur- 

 gonian. The Swiss geologists again divide the lower portion into two 

 members, — the lower and the middle Neocomian, represented by the 

 Marnes d'Hauterive and the yellow limestone J which underlies it. 



According to a letter from M. Desor, the Lower Neocomian is 

 characterized by Toxaster subquadratus, T. Campichei, and Pygurus 

 rostratus ; the upper, by Toxaster oblongus and Pygurus productus § . 

 It may be that the separation between the lower and the middle 

 Neocomian is only local ; it is certain, however, that the Hils-con- 

 glomerate has not as yet afforded any of the lower or of the upper 



* [This species, which M. v Strombeck states he has not received from Neu- 

 ehatel, has certainly been found in the Marnes d'Hauterive of Ste. Croix (Jura 

 Vaudoise).— E. R.] 



t [This species is found in the Neuchatel district in the Upper Neocomian 

 (etage urgonien). — E. R.] 



X [M. V. Strombeck speaks of this rock as being palaeontologically equivalent to 

 the Marnes d'Hauterive ; but this is incorrect, as the fauna is very different M. 

 Desor has proposed for this lower stage the name Valangien, and is about to 

 describe the fauna, which contains a great number of new species. — E. R.] 



§ [In M. V. Strombeck's paper the two species of Pygurus are inadvertently 

 misplaced one for the other. — E. R.] 



